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Explore various aspects of pollution, such as air pollution causes and effects, acid precipitation, greenhouse effect, global warming, ozone depletion, and indoor air pollution. Understand how human activities impact the environment and learn about measures to conserve resources and lower pollution levels.
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Table of Contents Chapter 19: Conserving Resources Section 2: Pollution
Pollution 2 A. Keeping the Environment Healthy— Air Pollution • A pollutant is a substance that contaminates the environment. • Air pollutants include soot, smoke, ash, and gases such as carbon dioxide, carbon monoxide, nitrogen oxides, and sulfur oxides.
Pollution 2 A. Keeping the Environment Healthy— Air Pollution • 3. Cars, trucks, airplanes, factories, homes, or power plants cause air pollution. • 4. Air pollution also can be caused by volcanic eruptions, wind-blown dust and sand, forest fires, and the evaporation of paints and other chemicals.
Pollution 2 A. Keeping the Environment Healthy— Air Pollution 5. Smog is a form of air pollution created when sunlight reacts with pollutants produced by burning fuels. 6. It can irritate the eyes and make breathing difficult for people with asthma or other lung diseases.
Pollution 2 A. Keeping the Environment Healthy— Air Pollution 7. Smog can be reduced if more people take buses or trains instead of driving. 8. Other vehicles, such as electric cars, that produce fewer pollutants also can help reduce smog.
Pollution 2 B. Acid Precipitation • Air pollutants from the burning of fossil fuels can react with water in the atmosphere to form strong acids. • Acidity is measured by a value called pH. • Acid Precipitationhas a pH below 5.6.
Pollution 2 C. Effects of Acid Rain • Acid precipitation ,or acid rain, washes nutrients from the soil, which can lead to the death of trees and other plants. • Runoff from acid rain that flows into a lake or pond can lower the pH of the water. • If algae and microscopic organisms cannot survive in the acidic water, fish and other organisms that depend on them for food also die.
Pollution 2 D. Greenhouse Effect 1. When sunlight reaches Earth’s surface, some of it is reflected back into space. The rest is trapped by atmospheric gases.
Pollution 2 D. Greenhouse Effect 2. This heat-trapping feature of the atmosphere is the greenhouse effect. 3. Without green house effect, temperatures on Earth probably would be too cold to support life. Click image to view movie.
Pollution 2 D. Greenhouse Effect • 4. Atmospheric gases that trap heat are called greenhouse gases. • 5. One of the most important greenhouse gases is carbon dioxide (CO2), a normal part of the atmosphere. • 6. It is also a waste product that forms when fossil fuels are burned.
Pollution 2 D. Greenhouse Effect 7. Over the past century, more fossil fuels have been burned than ever before, increasing CO2 in the atmosphere. • 8. The atmosphere might be trapping more of the Sun’s heat, making Earth warmer. • 9. A rise in Earth’s average temperature is known as global warming.
Pollution 2 E. Global Warming 1. Temperature data collected from 1895 through 1995 indicate that Earth’s average temperature increased about 1°C during that 100-year period. 2. No one is certain whether this rise was caused by human activities or is a natural part of Earth’s weather cycle.
Pollution 2 E. Global Warming 3. Changing rainfall patterns could alter ecosystems and affect the kinds of crops that can be grown in different parts of the world. 4. The number of storms and hurricanes might increase. 5. The polar ice caps might begin to melt, raising sea levels and flooding coastal areas.
Pollution 2 F. Ozone Depletion • Ozone is a form of oxygen in the atmosphere. • Ozone molecules are made of three oxygen atoms. 3. They are formed in a chemical reaction between sunlight and oxygen.
Pollution 2 F. Ozone Depletion 4. About 20 km above Earth’s surface is a portion of the atmosphere known as the ozone layer. 5. The ozone layer absorbs some of the Sun’s harmful ultraviolet (UV) radiation.This radiation can damage living cells.
Pollution 2 F. Ozone Depletion 6. Every year, the ozone layer temporarily becomes thinner over each polar region during its spring season. 7. The thinning of the ozone layer is called ozone depletion. 8. This problem is caused by certain pollutant gases, especially chlorofluorocarbons (klor oh FLOR oh kar bunz) (CFCs). 9. CFCs react chemically with ozone, breaking apart the ozone molecules.
Pollution 2 G. Effects of Ozone Depletion Because of ozone depletion, the amount of UV radiation that reaches Earth’s surface could be increasing. UV radiation could be causing a rise in the number of skin cancer cases in humans. World governments and industries have agreed to stop making and using CFCs.
Pollution 2 G. Effects of Ozone Depletion 4. Although the ozone that is high in the atmosphere protects life, the ozone that is near Earth’s surface can be harmful. 5. Ozone is produced when fossil fuels are burned. This ozone stays in the lower atmosphere, where it pollutes the air. 6. Ozone damages the lungs and other sensitive tissues of animals and plants.
Pollution 2 H. Indoor Air Pollution Air pollution can occur indoors. Better insulation in today’s buildings reduces the flow of air into and out of a building, so air pollutants can build up indoors. Paints, carpets, glues, and adhesives, printers, and photocopy machines also give off dangerous gases. Formaldehyde is a carcinogen, which means it can cause cancer.
Pollution 2 I. Carbon Monoxide Carbon monoxide (CO) is a poisonous gas that is produced whenever charcoal, natural gas, kerosene, or other fuels are burned. CO poisoning can cause serious illness or death. Fuel-burning stoves and heaters must be designed to prevent CO from building up indoors. CO is colorless and odorless, so it is difficult to detect.
Pollution 2 J. Radon 1. Radon is a naturally occurring, radioactive gas that is given off by some types of rock and soil. 2. Radon has no color or odor. It can seep into basements and the lower floors of buildings. 3. Radon exposure is the second leading cause of lung cancer in this country.
Pollution 2 K. Water Pollution Air pollutants can drift into water or be washed out of the sky by rain. Rain can wash land pollutants into waterways. Pollution also enters water when people dump litter or waste materials into rivers, lakes, and oceans.
Pollution 2 L. Surface Water 1. Some water pollutants poison fish and other wildlife, and can be harmful to people who swim in or drink the water. 2. For example, pesticides used on farms can wash into lakes and streams. The chemicals can harm the insects that fish eat. The fish may die from a lack of food.
Pollution 2 L. Surface Water 3. Algal blooms are another water pollution problem. 4. Raw sewage and excess fertilizer contain large amounts of nitrogen. 5. If they are washed into a lake or pond, they can cause the rapid growth of algae.
Pollution 2 L. Surface Water • 6. When the algae die, they are decomposed by huge numbers of bacteria that use up much of the oxygen in the water. • 7. Fish and other organisms can die from a lack of oxygen in the water.
Pollution 2 M. Ocean Water Rivers and streams eventually flow into oceans, bringing their pollutants along. Polluted water can enter the ocean in coastal areas where factories, sewage-treatment plants, or shipping activities are located. Oil spills are a well-known ocean pollution problem.
Pollution 2 N. Groundwater Pollution can affect water that seeps underground. Groundwater is water that collects between particles of soil and rock.
Pollution 2 N. Groundwater 3. Goundwater comes from precipitation and runoff that soaks into the soil.
Pollution 2 N. Groundwater • 4. This water can flow slowly through permeable layers of rock called aquifers. • 5. If this water comes into contact with pollutants as it moves through the soil and into an aquifer, the aquifer could become polluted. • 6. Polluted groundwater is difficult—and sometimes impossible—to clean.
Pollution 2 O. Soil Loss The movement of soil from one place to another is called erosion (ih ROH zhun). Eroded soil that washes into a river or stream can block sunlight and slow photosynthesis. Eroded soil also can harm fish, clams, and other organisms. When a farmer plows a field or a forest is cut down, soil is left bare. Bare soil is more easily carried away by rain and wind.
Pollution 2 P. Soil Pollution Soil can become polluted when air pollutants drift to the ground or when water leaves pollutants behind as it flows through the soil. Soil also can be polluted when people toss litter on the ground or dispose of trash in landfills.
Pollution 2 Q. Solid Wastes Most of the trash that people throw away every week is dumped in landfills. Most landfills are designed to seal out air and water to keep pollutants from seeping into surrounding soil. However, this also slows normal decay process. Food scraps and paper, which usually break down quickly, can last for many year in landfills.
Pollution 2 Q. Solid Wastes 4. By reducing the amount of trash that people produce, the need for new landfills can also be reduced.
Pollution 2 R. Hazardous Wastes Waste materials that are harmful to human health or poisonous to living organisms are hazardous wastes. They include dangerous chemicals, such as pesticides, oil, and petroleum-based solvents used in industry. They also include radioactive wastes from nuclear power plants, from hospitals that use radioactive materials to treat disease, and from nuclear weapons production.
Pollution 2 R. Hazardous Wastes 4. Many household items also are considered hazardous. 5. If these materials are dumped into landfills, they could seep into the soil, surface water, or groundwater over time.
Section Check 2 Question 1 A _______ is a substance that contaminates the environment.
Section Check 2 Question 2 Which strips nutrients from the soil? A. acid rain B. air pollution C. greenhouse effect D. ozone depletion
Section Check 2 Question 3 Which letter represents the ozone layer? A. A B. B C. C D. D
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